[Bug c++/84126] [8 Regression] ICE in variadic generic lambda inside a template function calling a function with arguments by reference

["benni.buch at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84126

Benjamin Buch <benni.buch at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |---

--- Comment #6 from Benjamin Buch <benni.buch at gmail dot com> ---
Thanks for fixing!

Found a variable template version that is still broken:


template <typename ... Ts>
void sink(Ts...){}

template <typename T>
int bar(T&){} // ICE with reference, work with just T

template <typename T>
auto var = [](auto ... k){
        sink(bar(k) ...);
    }(0);


int main() {
    var<int>;
}


$ g++ -std=c++14 main2.cpp
main2.cpp: In function 'int bar(T&)':
main2.cpp:5:13: warning: no return statement in function returning non-void
[-Wreturn-type]
 int bar(T&){} // ICE with reference, work with just T
             ^
main2.cpp: In instantiation of '<lambda(auto:1 ...)> [with auto:1 = {int}]':
main2.cpp:10:6:   required from 'auto var<int>'
main2.cpp:14:5:   required from here
main2.cpp:9:13: internal compiler error: Segmentation fault
         sink(bar(k) ...);
         ~~~~^~~~~~~~~~~~
0xe79ecf crash_signal
        ../../gcc/gcc/toplev.c:325
0x916d50 contains_struct_check(tree_node*, tree_node_structure_enum, char
const*, int, char const*)
        ../../gcc/gcc/tree.h:3245
0x916d50 enclosing_instantiation_of
        ../../gcc/gcc/cp/pt.c:12694
0x942a7e tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:11450
0x927dcd tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:17684
0x934e29 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:17100
0x934e29 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16838
0x933950 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16059
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x9311d8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16030
0x9311d8 instantiate_decl(tree_node*, bool, bool)
        ../../gcc/gcc/cp/pt.c:23384
0x87aeeb maybe_instantiate_decl
        ../../gcc/gcc/cp/decl2.c:5178
0x87ccf8 mark_used(tree_node*, int)
        ../../gcc/gcc/cp/decl2.c:5273
0x7e7c90 build_over_call
        ../../gcc/gcc/cp/call.c:8201
0x7f5f1c build_op_call_1
        ../../gcc/gcc/cp/call.c:4567
0x7f5f1c build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int)
        ../../gcc/gcc/cp/call.c:4596
0x970075 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
        ../../gcc/gcc/cp/semantics.c:2506
0x92849e tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:17874
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g++ (GCC) 8.0.1 20180202 (experimental)
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